Exhaust gas treatment method and exhaust gas treatment device

Abstract

The present invention provides an exhaust gas treatment method and an exhaust gas treatment device which prevent the generation of NOX, and treat a first exhaust gas and a second exhaust gas with a small amount of fuel, and the exhaust gas treatment method comprises a first combustion step which treats a first exhaust gas discharged from a carbonization furnace for carbonizing a fibrous substance in an inert atmosphere and a graphitization furnace for graphitizing a fibrous substance in an inert atmosphere and a second combustion step of treating a second exhaust gas discharged from a flameproofing furnace for flameproofing a fibrous substance in air atmosphere, wherein the first exhaust gas is combusted at an oxygen ratio of 0.8 or less in the first combustion step, and the second exhaust gas is combusted in the second combustion step using sensible heat and latent heat of a third exhaust gas discharged in the first combustion step.

The invention claimed is: 
     
       1. An exhaust gas treatment device comprising:
 a first combustion furnace which treats a first exhaust gas; 
 a second combustion furnace which treats a second exhaust gas; 
 a first exhaust gas supplying device which supplies the first exhaust gas into the first combustion furnace; 
 a second exhaust gas supplying device which supplies the second exhaust gas into the second combustion furnace; and 
 a first burner which is provided in the first combustion furnace, 
 wherein the second combustion furnace is provided on the secondary side of the first combustion furnace, and an internal space of the first combustion furnace and an internal space of the second combustion furnace communicate with each other, wherein the exhaust gas treatment device further comprises a first thermometer which measures a temperature in the first combustion furnace, a second thermometer which measures a temperature in the second combustion furnace, and a control unit which controls an amount of combustion of the first burner, and the amount of combustion of the first burner is controlled based on the temperatures obtained from the first thermometer and the second thermometer. 
 
     
     
       2. The exhaust gas treatment device according to  claim 1 , wherein oxygen-enriched air having an oxygen concentration of 25 to 100% by volume is used as a combustion-supporting gas of the first burner provided in the first combustion furnace. 
     
     
       3. The exhaust gas treatment device according to  claim 1 , wherein the first exhaust gas supplying device is the first burner and the first exhaust gas is supplied from the first burner. 
     
     
       4. The exhaust gas treatment device according to  claim 1 , wherein the first exhaust gas supplying device is a first blowing port provided in a wall of the first combustion furnace, and the first exhaust gas is supplied from the first blowing port. 
     
     
       5. The exhaust gas treatment device according to  claim 1 , wherein the second exhaust gas supplying device is a second blowing port provided in a wall of the second combustion furnace, and the second blowing port is configured so as to blow the second exhaust gas in a tangential direction of the wall of the second combustion furnace. 
     
     
       6. The exhaust gas treatment device according to  claim 1 , wherein the exhaust gas treatment device further comprises a heat exchanger at a stage subsequent to the exhaust gas treatment device, and the second exhaust gas is preheated using sensible heat of an exhaust gas discharged from the second combustion furnace. 
     
     
       7. The exhaust gas treatment device according to  claim 1 , wherein the first combustion furnace and the second combustion furnace each have an aperture, and the apertures are joined while being opposed to each other. 
     
     
       8. The exhaust gas treatment device according to  7 , wherein at least one of the first combustion furnace and the second combustion furnace has a throttle portion which regulates an aperture area of the aperture. 
     
     
       9. The exhaust gas treatment device according to  claim 1 , wherein the exhaust gas treatment device further comprises a communication pipe which is provided between the first combustion furnace and the second combustion furnace and allows the internal space of the first combustion furnace and the internal space of the second combustion furnace to communicate with each other. 
     
     
       10. An exhaust gas treatment method using the exhaust gas treatment device according to  claim 8  comprising:
 a first combustion step of treating a first exhaust gas discharged from a carbonization furnace for carbonizing a fibrous substance in an inert atmosphere and a graphitization furnace for graphitizing a fibrous substance in an inert atmosphere; and 
 a second combustion step of treating a second exhaust gas discharged from a flameproofing furnace for flameproofing a fibrous substance in air atmosphere; 
 wherein the first exhaust gas is combusted at an oxygen ratio of 0.8 or less in the first combustion step, and 
 the second exhaust gas is combusted in the second combustion step using sensible heat and latent heat of a third exhaust gas discharged in the first combustion step. 
 
     
     
       11. The exhaust gas treatment method according to  claim 10 , wherein the first exhaust gas is combusted at 1,000 to 1,600° C. in the first combustion step, and the second exhaust gas is combusted at 700 to 1,200° C. in the second combustion step. 
     
     
       12. An exhaust gas treatment device comprising:
 a first combustion furnace which treats a first exhaust gas; 
 a second combustion furnace which treats a second exhaust gas; 
 a first exhaust gas supplying device which supplies the first exhaust gas into the first combustion furnace; 
 a second exhaust gas supplying device which supplies the second exhaust gas into the second combustion furnace; and 
 a first burner which is provided in the first combustion furnace, 
 wherein the second combustion furnace is provided on the secondary side of the first combustion furnace, and an internal space of the first combustion furnace and an internal space of the second combustion furnace communicate with each other, wherein the exhaust gas treatment device further comprises a second burner which is provided in the second combustion furnace, and wherein the exhaust gas treatment device further comprises a first thermometer which measures a temperature in the first combustion furnace, a second thermometer which measures a temperature in the second combustion furnace, and a control unit which controls an amount of combustion of the first burner and the second burner, and the amount of combustion of the first burner and the second burner is controlled based on the temperatures obtained from the first thermometer and the second thermometer. 
 
     
     
       13. The exhaust gas treatment device according to  claim 12 , wherein oxygen-enriched air having an oxygen concentration of 25 to 100% by volume is used as a combustion-supporting gas of the first burner provided in the first combustion furnace. 
     
     
       14. The exhaust gas treatment device according to  claim 12 , wherein the first exhaust gas supplying device is the first burner and the first exhaust gas is supplied from the first burner. 
     
     
       15. The exhaust gas treatment device according to  claim 12 , wherein the first exhaust gas supplying device is a first blowing port provided in a wall of the first combustion furnace, and the first exhaust gas is supplied from the first blowing port. 
     
     
       16. The exhaust gas treatment device according to  claim 12 , wherein the second exhaust gas supplying device is a second blowing port provided in a wall of the second combustion furnace, and the second blowing port is configured so as to blow the second exhaust gas in a tangential direction of the wall of the second combustion furnace. 
     
     
       17. The exhaust gas treatment device according to  claim 12 , wherein the exhaust gas treatment device further comprises a heat exchanger at a stage subsequent to the exhaust gas treatment device, and the second exhaust gas is preheated using sensible heat of an exhaust gas discharged from the second combustion furnace. 
     
     
       18. The exhaust gas treatment device according to  claim 12 , wherein the first combustion furnace and the second combustion furnace each have an aperture, and the apertures are joined while being opposed to each other. 
     
     
       19. The exhaust gas treatment device according to  claim 18 , wherein at least one of the first combustion furnace and the second combustion furnace has a throttle portion which regulates an aperture area of the aperture. 
     
     
       20. The exhaust gas treatment device according to  claim 12 , wherein the exhaust gas treatment device further comprises a communication pipe which is provided between the first combustion furnace and the second combustion furnace and allows the internal space of the first combustion furnace and the internal space of the second combustion furnace to communicate with each other. 
     
     
       21. An exhaust gas treatment method using the exhaust gas treatment device according to  claim 12  comprising:
 a first combustion step of treating a first exhaust gas discharged from a carbonization furnace for carbonizing a fibrous substance in an inert atmosphere and a graphitization furnace for graphitizing a fibrous substance in an inert atmosphere; and 
 a second combustion step of treating a second exhaust gas discharged from a flameproofing furnace for flameproofing a fibrous substance in air atmosphere; 
 wherein the first exhaust gas is combusted at an oxygen ratio of 0.8 or less in the first combustion step, and 
 the second exhaust gas is combusted in the second combustion step using sensible heat and latent heat of a third exhaust gas discharged in the first combustion step. 
 
     
     
       22. The exhaust gas treatment method according to  claim 21 , wherein the first exhaust gas is combusted at 1,000 to 1,600° C. in the first combustion step, and the second exhaust gas is combusted at 700 to 1,200° C. in the second combustion step.